未捕获的类型错误：无法读取未定义的属性“说话”？
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【中文标题】未捕获的类型错误：无法读取未定义的属性“说话”？【英文标题】：Uncaught TypeError: Cannot read property 'speak' of undefined? 【发布时间】：2021-04-23 01:38:43 【问题描述】：我是 javascript 的新手，我看不到问题，因为整个代码都是正确的。 必须出现在控制台中的预期输出是：
Hello Yaakov
Good Bye John
Good Bye Jen
Good Bye Jason
Hello Paul
Hello Frank
Hello Larry
Hello Paula
Hello Laura
Good Bye Jim
但它一直告诉我无法读取属性“说话”。
/* script.js*/
(function()
var helloSpeaker;
var byeSpeaker;
var names = ["Yaakov", "John", "Jen", "Jason", "Paul", "Frank", "Larry", "Paula", "Laura", "Jim"];
for (var i = 0; i < names.length; i++)
var firstLetter = names[i].charAt(0).toLowerCase();
if (firstLetter === 'j')
byeSpeaker.speak(names[i]);
else
helloSpeaker.speak(names[i]);
)();
/* speakhello.js*/
(function(window)
var helloSpeaker = new Object();
var speakWord = "hello"
helloSpeaker.speak = function(name)
console.log(speakWord + "" + name);
;
window.helloSpeaker = helloSpeaker;
)(window);
/*speakgoodbye.js*/
(function(window)
var byeSpeaker = new Object();
var speakWord = "Good Bye";
byeSpeaker.speak = function(name)
console.log(speakWord + "" + name);
;
window.byeSpeaker = byeSpeaker;
)(window);<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Module 4 Solution Starter</title>
<script src="SpeakHello.js"></script>
<script src="SpeakGoodBye.js"></script>
<script src="script.js"></script>
</head>
<body>
<h1>Module 4 Solution Starter</h1>
</body>
</html>【问题讨论】：
【参考方案1】：不要在script.js 中声明局部变量helloSpeaker 和byeSpeaker。他们阻止访问在其他 JS 文件中分配的全局变量。
/* speakhello.js*/
(function(window)
var helloSpeaker = new Object();
var speakWord = "hello"
helloSpeaker.speak = function(name)
console.log(speakWord + "" + name);
;
window.helloSpeaker = helloSpeaker;
)(window);
/*speakgoodbye.js*/
(function(window)
var byeSpeaker = new Object();
var speakWord = "Good Bye";
byeSpeaker.speak = function(name)
console.log(speakWord + "" + name);
;
window.byeSpeaker = byeSpeaker;
)(window);
/* script.js*/
(function()
var names = ["Yaakov", "John", "Jen", "Jason", "Paul", "Frank", "Larry", "Paula", "Laura", "Jim"];
for (var i = 0; i < names.length; i++)
var firstLetter = names[i].charAt(0).toLowerCase();
if (firstLetter === 'j')
byeSpeaker.speak(names[i]);
else
helloSpeaker.speak(names[i]);
)();<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Module 4 Solution Starter</title>
<script src="SpeakHello.js"></script>
<script src="SpeakGoodBye.js"></script>
<script src="script.js"></script>
</head>
<body>
<h1>Module 4 Solution Starter</h1>
</body>
</html>【讨论】：
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